Combustor assembly

ABSTRACT

A combustor assembly for a gas turbine engine is includes a liner and a combustor dome formed of a ceramic matrix composite material. The combustor dome and liner together define at least in part a combustion chamber. The combustor dome extends along a circumferential direction and defines one or more openings, the combustor dome is configured to receive one or more fuel-air injector hardware assemblies in or through the one or more openings.

FEDERALLY SPONSORED RESEARCH

This invention was made with government support under contract numberW911W6-11-2-0009 of the U.S. Army. The government may have certainrights in the invention.

FIELD OF THE INVENTION

The present subject matter relates generally to a gas turbine engine, ormore particularly to a combustor assembly for a gas turbine engine.

BACKGROUND OF THE INVENTION

A gas turbine engine generally includes a fan and a core arranged inflow communication with one another. Additionally, the core of the gasturbine engine general includes, in serial flow order, a compressorsection, a combustion section, a turbine section, and an exhaustsection. In operation, air is provided from the fan to an inlet of thecompressor section where one or more axial compressors progressivelycompress the air until it reaches the combustion section. Fuel is mixedwith the compressed air and burned within the combustion section toprovide combustion gases. The combustion gases are routed from thecombustion section to the turbine section. The flow of combustion gassesthrough the turbine section drives the turbine section and is thenrouted through the exhaust section, e.g., to atmosphere.

More commonly, non-traditional high temperature materials, such asceramic matrix composite (CMC) materials, are being used as structuralcomponents within gas turbine engines. For example, typical combustionsections include an inner liner, an outer liner, and a dome. Morecommonly, the inner and outer liners are being formed of CMC materials,while the dome is formed of a metal material. The metal dome hasconventionally been required to attach certain fuel-air injectionassemblies.

However, certain gas turbine engines have had problems accommodatingcertain mechanical properties of the CMC materials incorporated therein.For example, CMC materials have different coefficients of thermalexpansion than the traditional metal materials. Accordingly, certaincombustor assemblies include attachment assemblies that may disrupt aflow of combustion gasses through the combustion chamber. Additionally,it can be difficult to mount certain components to CMC materials withoutrequiring duplicative and complicating metal parts.

Accordingly, a combustor assembly capable of using CMC materials withoutrequiring or including additional or duplicative metal components forattachment, and without creating aerodynamic hurdles for a flow ofcombustion gasses through the combustion chamber would be useful.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

In one exemplary embodiment of the present disclosure, a combustorassembly for a gas turbine engine defining a circumferential directionis provided. The combustor assembly includes a liner and a combustordome formed of a ceramic matrix composite material. The combustor domeand the liner together define at least in part a combustion chamber. Thecombustor dome defines an opening. The combustor assembly additionallyincludes a fuel-air injector hardware assembly attached directly to thecombustor dome and extending into or through the opening.

In another exemplary embodiment of the present disclosure, a combustorassembly for a gas turbine engine defining a circumferential directionis provided. The combustor assembly includes a liner and a combustordome formed of a ceramic matrix composite material. The combustor domeand the liner together define at least in part a combustion chamber. Thecombustor dome additionally defines a plurality of openings forreceiving a respective plurality of fuel-air injector hardwareassemblies.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1 is a schematic cross-sectional view of an exemplary gas turbineengine according to various embodiments of the present subject matter.

FIG. 2 is a perspective view of a combustor assembly in accordance withan exemplary embodiment of the present disclosure.

FIG. 3 is a side, cross-sectional view of the exemplary combustorassembly of FIG. 2.

FIG. 4 is a close-up, side, cross-sectional view of the exemplarycombustor assembly of FIG. 2.

FIG. 5 is a close-up, side, cross-sectional view of an opening in acombustor dome of the exemplary combustor assembly of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to present embodiments of theinvention, one or more examples of which are illustrated in theaccompanying drawings. The detailed description uses numerical andletter designations to refer to features in the drawings. Like orsimilar designations in the drawings and description have been used torefer to like or similar parts of the invention. As used herein, theterms “first”, “second”, and “third” may be used interchangeably todistinguish one component from another and are not intended to signifylocation or importance of the individual components. The terms“upstream” and “downstream” refer to the relative direction with respectto fluid flow in a fluid pathway. For example, “upstream” refers to thedirection from which the fluid flows, and “downstream” refers to thedirection to which the fluid flows.

Referring now to the drawings, wherein identical numerals indicate thesame elements throughout the figures, FIG. 1 is a schematiccross-sectional view of a gas turbine engine in accordance with anexemplary embodiment of the present disclosure. More particularly, forthe embodiment of FIG. 1, the gas turbine engine is a high-bypassturbofan jet engine 10, referred to herein as “turbofan engine 10.” Asshown in FIG. 1, the turbofan engine 10 defines an axial direction A(extending parallel to a longitudinal centerline 12 provided forreference), a radial direction R, and a circumferential direction (notshown) extending about the axial direction A. In general, the turbofan10 includes a fan section 14 and a core turbine engine 16 disposeddownstream from the fan section 14.

The exemplary core turbine engine 16 depicted generally includes asubstantially tubular outer casing 18 that defines an annular inlet 20.The outer casing 18 encases and the core turbine engine 16 includes, inserial flow relationship, a compressor section including a booster orlow pressure (LP) compressor 22 and a high pressure (HP) compressor 24;a combustion section 26; a turbine section including a high pressure(HP) turbine 28 and a low pressure (LP) turbine 30; and a jet exhaustnozzle section 32. A high pressure (HP) shaft or spool 34 drivinglyconnects the HP turbine 28 to the HP compressor 24. A low pressure (LP)shaft or spool 36 drivingly connects the LP turbine 30 to the LPcompressor 22. The compressor section, combustion section 26, turbinesection, and nozzle section 32 together define a core air flowpath 37.

For the embodiment depicted, the fan section 14 includes a variablepitch fan 38 having a plurality of fan blades 40 coupled to a disk 42 ina spaced apart manner. As depicted, the fan blades 40 extend outwardlyfrom disk 42 generally along the radial direction R. Each fan blade 40is rotatable relative to the disk 42 about a pitch axis P by virtue ofthe fan blades 40 being operatively coupled to a suitable pitch changemechanism 44 configured to collectively vary the pitch of the fan blades40 in unison. The fan blades 40, disk 42, and pitch change mechanism 44are together rotatable about the longitudinal axis 12 by LP shaft 36across a power gear box 46. The power gear box 46 includes a pluralityof gears for adjusting the rotational speed of the fan 38 relative tothe LP shaft 36 to a more efficient rotational fan speed.

Referring still to the exemplary embodiment of FIG. 1, the disk 42 iscovered by a rotatable front hub 48 aerodynamically contoured to promotean airflow through the plurality of fan blades 40. Additionally, theexemplary fan section 14 includes an annular fan casing or outer nacelle50 that circumferentially surrounds the fan 38 and/or at least a portionof the core turbine engine 16. The exemplary nacelle 50 is supportedrelative to the core turbine engine 16 by a plurality ofcircumferentially-spaced outlet guide vanes 52. Moreover, a downstreamsection 54 of the nacelle 50 extends over an outer portion of the coreturbine engine 16 so as to define a bypass airflow passage 56therebetween.

During operation of the turbofan engine 10, a volume of air 58 entersthe turbofan 10 through an associated inlet 60 of the nacelle 50 and/orfan section 14. As the volume of air 58 passes across the fan blades 40,a first portion of the air 58 as indicated by arrows 62 is directed orrouted into the bypass airflow passage 56 and a second portion of theair 58 as indicated by arrow 64 is directed or routed into the core airflowpath 37, or more specifically into the LP compressor 22. The ratiobetween the first portion of air 62 and the second portion of air 64 iscommonly known as a bypass ratio. The pressure of the second portion ofair 64 is then increased as it is routed through the high pressure (HP)compressor 24 and into the combustion section 26, where it is mixed withfuel and burned to provide combustion gases 66.

The combustion gases 66 are routed through the HP turbine 28 where aportion of thermal and/or kinetic energy from the combustion gases 66 isextracted via sequential stages of HP turbine stator vanes 68 that arecoupled to the outer casing 18 and HP turbine rotor blades 70 that arecoupled to the HP shaft or spool 34, thus causing the HP shaft or spool34 to rotate, thereby supporting operation of the HP compressor 24. Thecombustion gases 66 are then routed through the LP turbine 30 where asecond portion of thermal and kinetic energy is extracted from thecombustion gases 66 via sequential stages of LP turbine stator vanes 72that are coupled to the outer casing 18 and LP turbine rotor blades 74that are coupled to the LP shaft or spool 36, thus causing the LP shaftor spool 36 to rotate, thereby supporting operation of the LP compressor22 and/or rotation of the fan 38.

The combustion gases 66 are subsequently routed through the jet exhaustnozzle section 32 of the core turbine engine 16 to provide propulsivethrust. Simultaneously, the pressure of the first portion of air 62 issubstantially increased as the first portion of air 62 is routed throughthe bypass airflow passage 56 before it is exhausted from a fan nozzleexhaust section 76 of the turbofan 10, also providing propulsive thrust.The HP turbine 28, the LP turbine 30, and the jet exhaust nozzle section32 at least partially define a hot gas path 78 for routing thecombustion gases 66 through the core turbine engine 16.

It should be appreciated, however, that the exemplary turbofan engine 10depicted in FIG. 1 is provided by way of example only, and that in otherexemplary embodiments, the turbofan engine 10 may have any othersuitable configuration. It should also be appreciated, that in stillother exemplary embodiments, aspects of the present disclosure may beincorporated into any other suitable gas turbine engine. For example, inother exemplary embodiments, aspects of the present disclosure may beincorporated into, e.g., a turboprop engine, a turboshaft engine, or aturbojet engine.

Referring now to FIGS. 2 and 3, views are provided of a combustorassembly 100 for a gas turbine engine in accordance with an exemplaryembodiment of the present disclosure. For example, the combustorassembly 100 of FIGS. 2 and 3 may be positioned in the combustionsection 26 of the exemplary turbofan engine 10 of FIG. 1, which definesan axial direction A, a radial direction R, and a circumferentialdirection C. More particularly, FIG. 2 provides a perspective view ofthe combustor assembly 100 and FIG. 3 provides a side, schematic,cross-sectional view of the exemplary combustor assembly 100 of FIG. 2.

As shown, the combustor assembly 100 generally includes a combustor dome102 and a combustion chamber liner. For the embodiment depicted, thecombustion chamber liner is configured as a combustion chamber outerliner 104, and the combustor dome 102 and combustion chamber outer liner104 are formed integrally of a ceramic matrix composite (“CMC”)material. CMC material is a non-metallic material having hightemperature capability. Exemplary CMC materials utilized for thecombustor dome 102 and combustion chamber liners (e.g., the outer liner104) may include silicon carbide, silicon, silica or alumina matrixmaterials and combinations thereof. Ceramic fibers may be embeddedwithin the matrix, such as oxidation stable reinforcing fibers includingmonofilaments like sapphire and silicon carbide (e.g., Textron's SCS-6), as well as rovings and yarn including silicon carbide (e.g.,Nippon Carbon's NICALON®, Ube Industries' TYRANNO®, and Dow Corning'sSYLRAMIC®), alumina silicates (e.g., Nextel's 440 and 480), and choppedwhiskers and fibers (e.g., Nextel's 440 and SAFFIL®), and optionallyceramic particles (e.g., oxides of Si, Al, Zr, Y and combinationsthereof) and inorganic fillers (e.g., pyrophyllite, wollastonite, mica,talc, kyanite and montmorillonite).

Additionally, the combustor dome 102 and combustion chamber outer liner104 extend along the circumferential direction C and are formedintegrally of a single, continuously formed piece of CMC material. Moreparticularly, the combustor dome 102 and combustion chamber outer liner104 each extend continuously along the circumferential direction C todefine an annular shape, without any seams or joints where separatepieces are combined by, e.g., bolting. It will be appreciated that asused herein, a CMC component form integrally of a single, continuouslyformed piece of CMC material includes a component formed of overlappingand non-overlapping strips or sheets of CMC formed together using aresin or other suitable joining compound.

As may be seen most clearly in FIG. 3, combustor assembly 100additionally includes a combustion chamber inner liner 106. Similar tothe combustor dome 102 and combustion chamber outer liner 104, thecombustion chamber inner liner 106 also extends continuously along thecircumferential direction C to define an annular shape. As will bediscussed in greater detail below, the combustion chamber inner liner106 is joined to the combustor dome 102, such that the combustionchamber inner liner 106 and the integrally formed combustion chamberouter liner 104 and combustor dome 102 together define an annularcombustion chamber 108. Accordingly, the exemplary combustor assembly100 depicted is configured as an annular combustor.

Referring to FIG. 3 in particular, the combustion chamber outer liner104 and combustion chamber inner liner 106 each extend generally alongthe axial direction A—the combustion chamber outer liner 104 extendingbetween a forward end 110 and an aft end 112 and the combustion chamberinner liner 106 similarly extending between a forward end 114 and an aftend 116. Additionally, the combustor dome 102 includes a forward wall118 and a transition portion. Specifically, the combustor dome 102depicted includes an outer transition portion 120 and an innertransition portion 122. The outer transition portion 120 is positionedalong an outer edge of the forward wall 118 along the radial direction Rand the inner transition portion 122 is positioned along an inner edgeof the forward wall 118 along the radial direction R. The inner andouter transition portions 122, 120 each extend circumferentially withthe forward wall 118 of the combustor dome 102 (see a FIG. 2).

Further, the outer transition portion 120 extends from the forward wall118 towards the outer liner 104 and the inner transition portion 122extends from the forward wall 118 towards the inner liner 106. Asstated, for the embodiment depicted the outer liner 104 is formedintegrally with the combustor dome 102 (including the forward wall 118and the outer transition portion 120), and thus the outer transitionportion 120 extends seamlessly from the forward wall 118 to the outerliner 104. For example, the combustor dome 102 and combustion chamberouter liner 104 together define a continuous and seamless surfaceextending from the combustor dome 102 to the combustion chamber outerliner 104. More particularly, the combustor dome 102 and combustionchamber outer liner 104 together define a continuous and seamless insidesurface 124 (i.e., facing the combustion chamber 108) and a continuousand seamless outside surface 126 (opposite the inside surface 124).

Referring now briefly to FIG. 4, providing a close-up, cross-sectional,schematic view of a forward end of the combustor assembly 100 of FIGS. 2and 3, the outer transition portion 120 and inner transition portion 122each define an angle relative to the forward wall 118. For theembodiment depicted, the outer transition portion 120 and innertransition portion 122 each define an angle 132, 133, respectively,greater than ninety degrees (90°) and less than one hundred and eightydegrees (180°) relative to the forward wall 118. More specifically, theouter transition portion 120 includes a flat 128 (i.e., a substantiallyflat portion as viewed in the cross-sectional plane depicted in FIG. 4)and the inner transition portion 122 similarly includes a flat 130. Theflats 128, 130 of the outer transition portion 120 and inner transitionportion 122, respectively, each define an angle 132, 133 greater thanninety degrees (90°) and less than one hundred and eighty degrees (180°)relative to the forward wall 118. Specifically, for the embodimentdepicted, the angles 132, 133 of the flats 120, 130 relative to theforward wall 118 is between about one hundred and twenty degrees (120°)and one hundred and fifty degrees (150°), such as about one hundred andthirty-five degrees (135°). It should be appreciated, that as usedherein, terms of approximation, such as “about” or “approximately,”refer to being within a ten percent (10%) margin of error.

As may also be seen in FIG. 4, the exemplary combustor dome 102additionally defines an outer radius of curvature 134 between the outerflat 128 of the outer transition portion 120 and the forward wall 118.Notably, the forward wall 118 defines a length 140 between the outerflat 128 and the inner flat 130. In certain exemplary embodiments, theouter radius of curvature 134 may be between about two percent (2%) andabout twenty percent (20%) of the length 140 of the forward wall 118.For example, the outer radius of curvature 134 may be between about fivepercent (5%) and about fifteen percent (15%) of the length 140 of theforward wall 118, or between about eight percent (8%) and about twelvepercent (12%) of the length 140 of the forward wall 118. Similarly, thecombustor dome 102 may define an inner radius of curvature 136 betweenthe inner flat 130 of the inner transition portion 122 and the forwardwall 118. The inner radius of curvature 136 may in certain embodiments,have the same value as the outer radius of curvature 134. It should beappreciated, that as used herein, the term “radius of curvature” refersto radius of a circle that touches a curve at a given point and has thesame tangent and curvature at that point.

Moreover, in the cross-sectional plane depicted in FIG. 4, the flat 128of the outer transition portion 120 defines a length 138 and, as stated,the forward wall 118 of the combustor dome 102 also defines the length140. The length 138 of the flat 128 may be between about ten percent(10%) and about thirty-five percent (35%) of the length 140 of theforward wall 118 of the combustor dome 102. For example, the length 138of the flat 128 may be between about fifteen percent (15%) and aboutthirty percent (30%) of the length 140 of the forward wall 118, orbetween about twenty percent (20%) and about twenty-five percent (25%)of the length 140 of the forward wall 118. Further, as is depicted, theflat 130 of the inner transition portion 122 also defines a length 142in the cross-sectional plane depicted. The length 142 of the flat 130 ofthe inner transition portion 122 may also be between about ten percent(10%) and about thirty-five percent (35%) of the length 140 of theforward wall 118 of the combustor dome 102. For example, the length 142of the flat 130 may be between about fifteen percent (15%) and aboutthirty percent (30%) of the length 140 of the forward wall 118, orbetween about twenty percent (20%) and about twenty-five percent (25%)of the length 140 of the forward wall 118.

A combustor assembly in accordance with one or more embodiments of thepresent disclosure may provide for desirable flow characteristicsthrough the combustion chamber as well as around the combustion chamber(e.g., for cooling air flowing around the combustion chamber).Specifically, inclusion of an integrally formed combustion chamber outerliner and combustor dome, and/or inclusion of one or more of the innerand outer transition portions with the combustor dome, may allow formore desirable flow characteristics of combustion gasses through thecombustion chamber and to a turbine section of a gas turbine engine intowhich the combustor assembly is installed, as well as around thecombustion chamber. For example, inclusion of the transition portions inaccordance with an embodiment of the present disclosure may allowcooling flow along a hot side of the dome to blend with a cooling flowalong a hot side of the liners (introduced through one or more coolingholes on the liners). Such a configuration may thus allow for a coolingflow over portions of the transition portions where no cooling holes maybe present. Additionally, inclusion of the transition portions inaccordance with an embodiment of the present disclosure may allowsmoother cooling flow over the cold sides of the combustor dome andcombustor liners, which may provide for less pressure drop for a coolingair provided to downstream cooling holes in the combustor liners.Further, configuring the combustor dome, combustion chamber inner liner,and combustion chamber outer liner to each extend continuously along acircumferential direction may further increase the desirable flowcharacteristics of the combustion gases through the combustion chamberby eliminating any seams (such as any axially extending seams) betweencircumferentially spaced segments and by allowing for uniform thermalexpansion and contraction during operation of the combustor assembly.

It should be appreciated, however, that the exemplary combustor assembly100 depicted in FIGS. 2 through 4, and described herein, are provided byway of example only and that in other exemplary embodiments of thepresent disclosure, the combustor assembly 100 may have any othersuitable configuration. For example, in other exemplary embodiments, thecombustion chamber outer liner 104 may not be formed integrally with thecombustor dome 102, and instead may be attached to the combustor dome102 in any suitable manner. Further, in certain exemplary embodiments,the combustion chamber inner liner 106 may be integrally formed with thecombustor dome 102 instead of or in addition to the combustion chamberouter liner 104. Moreover, in still other embodiments, the combustordome 102 may have any other suitable configuration. For example, incertain embodiments, the combustor dome 102 may not include one or bothof the outer transition portion 120 or the inner transition portion 122.Or alternatively, one or both of the outer transition portion 120 or theinner transition portion 122 may be configured in any other suitablemanner.

Referring again to FIGS. 2 and 3, the outer transition portion 120 ofthe combustor dome 102, as stated, is formed integrally with and extendsseamlessly into the combustion chamber outer liner 104. By contrast,however, for the embodiment depicted the combustion chamber inner liner106 is formed separately from the combustor dome 102 and combustionchamber outer liner 104. The combustion chamber inner liner 106 isattached to the combustor dome 102 using a bolt 144. Specifically, thecombustion chamber inner liner 106 includes an attachment flange 146extending inward along the radial direction R at the forward end 114 andthe combustor dome 102 similarly includes an attachment flange 148extending inward along the radial direction R at a radially inner end.The bolt 144 extends through the flange 146 of the combustion chamberinner liner 106 and the flange 148 of the combustor dome 102 to attachthe two components. Notably, the combustion chamber inner liner 106 andcombustor dome 102 abut at an inner surface (i.e., facing the combustionchamber 108) to define a substantially continuous surface, with theexception of a single seam 150 extending circumferentially where the twocomponents are joined.

The bolt 144 is configured as part of a mounting assembly 152 of thecombustor assembly 100. The mounting assembly 152 generally includes asupport member 145 extending generally between a forward end 147 and anaft end 149, attaching to the combustion chamber inner liner 106 andcombustor dome 102 at the forward end 147. At the aft end 149, thesupport member is mountable to, e.g., a casing or other supportstructure within the gas turbine engine. Accordingly, the combustionchamber outer liner 104, combustor dome 102, and combustion chamberinner liner 106 may each be supported within the gas turbine engine at aforward end of the combustor assembly 100 (i.e., at the forward end 114of the inner liner 106) through the support member 145 of the mountingassembly 152.

Referring still to FIGS. 2 and 3, the combustor dome 102 additionallydefines an opening 154 and the combustor assembly 100 includes afuel-air injector hardware assembly 156. More particularly, thecombustor dome 102 defines a plurality of openings 154 and the combustorassembly 100 includes a respective plurality of fuel-air injectorhardware assemblies 156—each opening 154 configured for receiving arespective one of the plurality of fuel-air injector hardware assemblies156. For the embodiment depicted, each of the openings 154 aresubstantially evenly spaced along the circumferential direction C, ormore particularly are substantially evenly spaced from one another alongthe circumferential direction C.

The plurality of fuel-air injector hardware assemblies 156 may eachinclude, e.g., a swirler and/or a baffle. Generally, the fuel-airinjector hardware assemblies 156 are configured to receive a flow ofcombustible fuel from a fuel nozzle (not shown) and compressed air froma compressor section of a gas turbine engine in which the combustorassembly 100 is installed (see FIG. 1). The fuel-air injector hardwareassemblies 156 mix the fuel and compressed air and provide such fuel-airmixture to the combustion chamber 108. Although not depicted, an ignitermay extend at least partially into the combustion chamber 108 toinitially ignite the fuel-air mixture.

Referring now also to FIG. 5, providing a close-up, cross-sectional,schematic view of the combustor dome 102 and a fuel injector hardwareassembly 156, for the embodiment depicted, each fuel-air injectorhardware assembly 156 is attached directly to the combustor dome 102 anda respective one of the plurality of openings 154. Additionally, as isdepicted, each fuel-air injector hardware assembly 156 extends into orthrough such opening 154. More particularly, the combustor dome 102defines a hot side 158 exposed to the combustion chamber 108 and anopposite cold side 160. Although not depicted, combustor dome mayinclude a protective coating, such as an environmental protectivecoating, at the hot side 158 and/or the cold side 160. The combustordome 102 includes a raised boss 162 extending around each of theplurality of openings 154 in the combustor dome 102 on the cold side 160of the combustor dome 102, and a groove 164 extending around each of theplurality openings 154 in the combustor dome 102 on the hot side 158 ofthe combustor dome 102. The raised boss 162 and groove 164 of thecombustor dome 102 are configured for assisting with mounting thefuel-air injector hardware assemblies 156 directly to the combustor dome102.

Specifically, the raised boss 162 allows for a desired thickness, suchthat the fuel-air injector hardware assemblies 156 may be attacheddirectly to the combustor dome 102. For example, as is depicted thefuel-air injector hardware assemblies 156 are each attached directly tothe hot side 158 of the combustor dome 102 (i.e., at the groove 164) andto the cold side 160 of the combustor dome 102 (i.e., at the raised boss162). Notably, referring back to FIG. 2, at least one of the fuel-airinjector hardware assemblies 156 is attached directly to the combustordome 102 independently of an adjacent fuel-air injector hardwareassembly 156, or more specifically each of the fuel-air injectorhardware assemblies 156 are attached directly to the combustor dome 102independently of the adjacent fuel-air injector hardware assemblies 156.For example, as the combustor assembly 100 depicted includes a combustordome 102 extending continuously along the circumferential direction C,no additional or supplemental supports are required for the combustordome 102 and plurality of fuel-air injector hardware assemblies 156.

As may also be seen most clearly in FIG. 2, the combustor dome 102defines a plurality of cooling holes 166 extending through the combustordome 102 from the cold side 160 to the hot side 158 to allow for a flowof cooling air therethrough. As may be seen, the plurality of coolingholes 166 includes a plurality of cooling holes extending around andencircling at least one of the openings 154 defined in the combustordome 102 for receiving the respective fuel-air injector hardwareassemblies 156. Particularly, for the embodiment depicted, the pluralityof cooling holes 166 include a plurality of cooling holes extendingaround and encircling each of the openings 154 defined in the combustordome 102. Additionally, the combustor dome 102 includes a variety ofadditional cooling holes 166 defined in the forward wall 118 of thecombustor dome 102. Further, the combustor dome 102 defines a pluralityof cooling holes 166 extending through the outer transition portion 120of the combustor dome 102 and the inner transition portion 122 of thecombustor dome 102 (see, e.g., FIG. 3) from the cold side 160 to the hotside 158 to allow for a flow of cooling air therethrough. Moreover, thecombustion chamber outer liner 104 includes a plurality of cooling holes166 extending therethrough in a similar manner to allow for anadditional amount of cooling air to flow therethrough. The cooling airmay be provided from a compressor section of a gas turbine engine intowhich the combustor assembly 100 is installed.

Inclusion of an integrally formed combustion chamber liner and combustordome, and/or a combustor dome having one or both of an inner transitionportion or outer transition portion, may allow for direct localizedcooling of certain areas of the components forming the combustionchamber without substantially disrupting a flow of combustion gassesthrough the combustion chamber.

It should be appreciated, however, that the exemplary embodimentdepicted in FIGS. 2 through 5 is provided by way of example only, andthat in other exemplary embodiments, the combustor assembly 100 may haveany other suitable configuration. For example, in other exemplaryembodiments, the fuel-air injector hardware assemblies 156 may beconfigured in any other suitable manner, and also may be attached to thecombustor dome 102 in any other suitable manner. Further, in otherexemplary embodiments, one or more of the combustion chamber outer liner104, combustor dome 102, and combustion chamber inner liner 106 may haveany other suitable configuration of cooling holes 166 or other coolingmeans for maintaining a temperature of such components within a desiredtemperature range.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A combustor assembly for a gas turbine enginedefining a circumferential direction, the combustor assembly comprising:a liner; a combustor dome formed of a ceramic matrix composite material,the combustor dome and the liner together defining at least in part acombustion chamber, the combustor dome defining an opening; and afuel-air injector hardware assembly attached directly to the combustordome and extending into or through the opening; wherein the combustordome includes a raised boss extending around the opening in thecombustor dome for mounting the fuel-air injector hardware assemblydirectly to the combustor dome.
 2. The combustor assembly of claim 1,wherein the fuel-air injector hardware assembly comprises a plurality offuel-air injector hardware assemblies, and wherein at least one fuel-airinjector hardware assembly is attached directly to the combustor domeindependently of an adjacent fuel-air injector hardware assembly.
 3. Thecombustor assembly of claim 1, wherein the fuel-air injector hardwareassembly comprises a plurality of fuel-air injector hardware assemblies,and wherein each fuel-air injector hardware assembly is attacheddirectly to the combustor dome independently of the adjacent fuel-airinjector hardware assemblies.
 4. The combustor assembly of claim 1,wherein the combustor dome defines a hot side and a cold side, andwherein the fuel-air injector hardware assembly is attached directly tothe hot side of the combustor dome and directly to the cold side of thecombustor dome.
 5. The combustor assembly of claim 1, wherein thecombustor dome extends continuously along the circumferential directionand is formed integrally of a continuous piece of ceramic matrixcomposite material.
 6. The combustor assembly of claim 1, wherein thecombustor dome further defines a plurality of openings, and wherein theplurality of openings are substantially evenly spaced along thecircumferential direction.
 7. The combustor assembly of claim 1, whereinthe combustor dome defines a hot side and a cold side, and wherein thecombustor dome defines a plurality of cooling holes extending throughthe combustor dome from the cold side to the hot side to allow for aflow of cooling air.
 8. The combustor assembly of claim 7, wherein theplurality of cooling holes includes a plurality of cooling holesextending around the opening for receiving the fuel-air injectorhardware assembly.
 9. The combustor assembly of claim 1, wherein thecombustor dome comprises a transition portion and a back wall, whereinthe transition portion extends from the back wall of the combustor dometowards the liner, and wherein the transition portion defines an anglegreater than 90 degrees and less than 180 relative to the back wall. 10.A combustor assembly for a gas turbine engine defining a circumferentialdirection, the combustor assembly comprising: a liner; and a combustordome formed of a ceramic matrix composite material, the combustor domeand the liner together defining at least in part a combustion chamber,the combustor dome defining a plurality of openings for receiving arespective plurality of fuel-air injector hardware assemblies, whereinthe combustor dome extends along the circumferential direction and isformed integrally of a continuous piece of ceramic matrix compositematerial; wherein the combustor dome includes a raised boss extendingaround each of the plurality of openings in the combustor dome formounting a respective fuel-air injector hardware assembly directly tothe combustor dome.
 11. The combustor assembly of claim 10, wherein thecombustor dome extends continuously along the circumferential directionto define an annular shape.
 12. The combustor assembly of claim 10,wherein the plurality of openings are substantially evenly spaced alongthe circumferential direction.
 13. The combustor assembly of claim 10,further comprising: a plurality of fuel-air injector hardwareassemblies, each fuel-air injector hardware assembly attached directlyto the combustor dome at a respective one of the plurality of openings.14. The combustor assembly of claim 13, wherein each fuel-air injectorhardware assembly is attached directly to the combustor domeindependently of an adjacent fuel-air injector hardware assembly. 15.The combustor assembly of claim 13, wherein at least one fuel-airinjector hardware assembly is attached directly to the combustor domeindependently of an adjacent fuel-air injector hardware assembly. 16.The combustor assembly of claim 10, wherein the combustor dome defines ahot side facing the combustion chamber and a cold side opposite the hotside, and wherein the combustor dome includes an environmentalprotective coating on at least one of the hot side or the cold side. 17.The combustor assembly of claim 10, wherein the combustor dome defines ahot side and a cold side, and wherein the combustor dome defines aplurality of cooling holes extending through the combustor dome from thecold side to the hot side to allow for a flow of cooling air.
 18. Thecombustor assembly of claim 10, wherein the combustor dome includes agroove extending around each of the plurality of openings in thecombustor dome on the hot side of the combustor dome, wherein the raisedboss and the groove of the combustor dome are configured for assistingwith mounting the fuel-air injector hardware assemblies directly to thecombustor dome.